Matt Hancock, the Health Secretary, said the data shows “more and more of us are benefiting from protection the vaccine gives us against this awful disease”.
Speaking at a Downing Street press briefing on Wednesday, Mr Hancock said the presence of antibodies was a “measure of the protection that we have collectively built up right across the country”.
“In the older age groups, those who got vaccinated first are much more likely to have Covid-19 antibodies,” he added. “Now seven in 10 adults have protective Covid-19 antibodies – this is the vaccination programme in action.”
Officials suggested the latest figures, for the week ending April 11, may even underestimate the levels of protection as antibodies are not the only part of the immune system to respond to vaccination. The ONS data tracked more than 20,000 people to measure antibodies in their blood.
Prof Jonathan Van-Tam, the deputy chief medical officer, said it was not yet known how far antibodies protect against new Covid variants. He said he hoped that even if they were less able to combat infections, protection against severe disease would remain “much more solid”.
Ministers on Wednesday announced that they had secured 60 million more doses of the Pfizer vaccine, which will be used for booster jabs to protect against new variants in the autumn.
Enough doses have been secured to cover the whole country, but decisions about how the programme is rolled out have yet to be taken by the joint committee on vaccination and immunisation (JCVI).
Officials said the Government was preparing for a booster programme “based on clinical need” which would protect the most vulnerable ahead of winter. It comes as new data from Public Health England shows that one dose of a Covid-19 vaccine reduces household transmission of the virus by up to half.